762 research outputs found
Microbiome profiling reveals a microbial dysbiosis during a natural outbreak of tenacibaculosis (Yellow Mouth) in Atlantic salmon
No full textTenacibaculosis remains a major health issue for a number of important aquaculture species globally. On the west coast of Canada, yellow mouth (YM) disease is responsible for significant economic loss to the Atlantic salmon industry. While Tenacibaculum maritimum is considered to be the primary agent of clinical YM, the impact of YM on the resident microbial community and their influence on the oral cavity is poorly understood. Using a 16s rRNA amplicon sequencing analysis, the present study demonstrates a significant dysbiosis and a reduction in diversity of the microbial community in the YM affected Atlantic salmon. The microbial community of YM affected fish was dominated by two amplicon sequence variants (ASVs) of T. maritimum, although other less abundant ASVs were also found. Interestingly clinically unaffected (healthy) and YM surviving fish also had a high relative abundance of T. maritimum, suggesting that the presence of T. maritimum is not solely responsible for YM. A statistically significant association was observed between the abundance of T. maritimum and increased abundance of Vibrio spp. within fish displaying clinical signs of YM. Findings from our study provide further evidence that YM is a complex multifactorial disease, characterized by a profound dysbiosis of the microbial community which is dominated by distinct ASVs of T. maritimum. Opportunistic taxa, including Vibrio spp., may also play a role in clinical disease progression.Commonwealth Scientific and Industrial Research OrganisationCanada Excellence Research ChairsUniversity of Prince Edward Islan
A class of Frattini-like subgroups of a finite group
No full textAbstractLet G be a finite group and π a set of primes. We consider the families of subgroups of G:F1 = {M: M ⋖ G, |G : M|π = 1}F2 = {M: M ⋖ G, |G : M|π = 1, |G : M| is composite}. Denote Φπ(G) = ∩ {M: M ϵ F1} if F1 is nonempty, otherwise Φπ(G) = G and Sπ (G) = ∩ {M: M ϵ F2} if F2 is nonempty, otherwise Sπ(G) = G. The purpose of this paper is to investigate these subgroups further
Resonant coupling of a SQUID to a mechanical resonator
No full textWe analyze the properties of a mechanical resonator embedded into a quantum SQUID and analyze under which conditions it is possible to realize a resonant coupling between the SQUID and the resonator. We find, within the present technology, how it is possible to tune the system into the regime where the plasma frequency of the SQUID matches the resonator frequency and maximizes the corresponding coupling. In these conditions the doubly degenerate quantum level of the system is split by the coupling between the SQUID and the resonator.QN/Quantum NanoscienceApplied Science
Detecting phonon blockade with photons
No full textMeasuring the quantum dynamics of a mechanical system, when few phonons are involved, remains a challenge. We show that a superconducting microwave resonator linearly coupled to the mechanical mode constitutes a very powerful probe for this scope. This new coupling can be much stronger than the usual radiation pressure interaction by adjusting a gate voltage. We focus on the detection of phonon blockade, showing that it can be observed by measuring the statistics of the light in the cavity. The underlying reason is the formation of an entangled state between the two resonators. Our scheme realizes a phonotonic Josephson junction, giving rise to coherent oscillations between phonons and photons as well as a self-trapping regime for a coupling smaller than a critical value. The transition from the self-trapping to the oscillating regime is also induced dynamically by dissipation.QN/Quantum NanoscienceApplied Science
Improving the engineering strength of heat strengthened glass
No full textAlthough glass is increasingly used as a structural material, glass is not produced to strength standards, like steel and concrete. Of the three types of glass: annealed, heat strengthened and fully tempered, only heat strengthened glass has the properties to function as a safe structural material. These properties are strength, resistance to stress corrosion cracking, and controlled fragmentation. In this paper the factors controlling the strength of heat strengthened glass are assessed. The dominant influence is the spread in compressive pre-strength. Opportunities for quality control of the compressive pre-strength are analysed using experimental results. The consequences for the predictability of the strength and the requirements for quality controlled are discussed
Morphological character evolution of Amorphophallus (Araceae) based on a combined phylogenetic analysis of trnL, rbcL, and LEAFY second intron sequences
No full textSequences of three different genes in 69 taxa of Amorphophallus were combined to reconstruct the molecular phylogeny of this species-rich Aroid genus. The data set was analyzed by three different methods, Maximum Parsimony, Maximum Likelihood and Bayesian analysis, producing slightly different tree topologies. Three major clades identified in all analyses reflect the biogeographical distribution of Amorphophallus. Some clades were supported by morphological characters such as sessile/nonsessile stigma, pollen opening mechanism, shape of the main segments of the lamina, growth cycle, and berry colour. When optimised, a nonsessile stigma may have evolved from a sessile one with several reversals. Pollen opening by connective rupturing evolved from pollen opening by pores. Unequally shaped segments of the lamina evolved from equally shaped segments. Simultaneously existing leaf and inflorescences evolved from alternating leaves and inflorescences. Blue, purple, green, and yellow berries evolved from red/orange/white ones
Modelling of Bifacial Gain for Stand-alone and in-field Installed Bifacial PV Modules
No full textAbstractBifacial solar cells enable the absorption of light also by the cell's rear side, hence increasing the energy yield of a bifacial module, Yb compared to the energy yield of a monofacial module installed under the same conditions, Ym, by BG = (Yb - Ym) / Ym, the bifacial gain. This contribution presents a simulation model for the prediction of the BG of bifacial PV modules (stand-alone and integrated in a PV field). The model has been implemented as a software tool and the results obtained by applying the tool to various relevant system configurations (ground albedo, geographical locations, module height and tilt, diffuse irradiation fraction) are shown. These results allow to determine the optimum installation parameters for highest BG for a given installation site. Finally, the tool is validated by comparing the simulated results with the actual BG monitored on bifacial modules during several months on an outdoor testing site
The use of yield management within the kingdom of Saudi Arabia hotels
No full textThe airline industry has successfully adopted yield management (YM), particularly after the industry was deregulated in the late 1970s. In this study, YM is applicable to the hotel industry as a strategy to maximise profits. Thus, it involves the allocation of resources among various customers in hotel rooms relative to the existing market characteristics. In doing so, YM’s core concept is the provision of the right service to customers at the right prices.
The aim of this study is to examine the practices and perceptions concerning YM as per the understanding and awareness of hotel managers. The study investigates several Saudi hotels of various sizes that use YM, and it identifies revenue management strategies and general practices within the hotel industry.
The investigation took place in seven key areas of the hotel industry: location, occupancy, pricing strategy, price-adjustment strategies, HR management, customer satisfaction and third-party websites. The study involved two steps to achieve its purpose. First, YM practices were investigated in comparison to the seven key areas that influence revenue. Moreover, there was an emphasis on determining whether there was an attempt to manage revenue within the hotel industry. The results from the investigation are presented using a descriptive approach. The second step involved establishing the use of YM as a tool for managing revenue in hotel operations. This shows how revenue management through YM should be conducted. These results are presented using a normative approach.
In the methodology, qualitative research is applied. Through this approach, 13 revenue managers and seven general managers from various Saudi hotels in Riyadh, the Eastern Province and Mecca were interviewed. Further, documents and direct observations were used to collect vital data to compare room rates through the use of direct and indirect distribution channels. Here, direct distribution channels involve making direct calls to hotels, as well as the use of official hotel websites. Conversely, indirect distribution channels involve the use of Booking.com and Agoda.com.
These different options were then compared to observe the option that was more efficient in revenue management. From the comparison, the results showed that the practices and perceptions of YM were reasonable in the cities’ hotels. Of particular interest was the fact that respondents were aware of some key principles of YM. Consequently, many of these principles had been adhered to in room revenue management. For instance, stakeholders understood the significance of segmenting potential and current customers into various groups. This is critical, as these groups have different priorities, income levels and goals. As a rule, attention focuses on criteria such as ability and willingness to pay.
The study recommends strategies that can be adopted by Saudi hotels to overcome the misconceptions and perceptions of YM. For instance, the system must be interlinked with location, occupancy, pricing strategy, price-adjustment strategy, HR, customer relations and the Internet. Interlinking the system with these key concepts is essential to maximise profits in the hotel industry. In essence, this paper offers knowledge to further the research on the applicability of the YM concept within the hotel industry in Saudi Arabia
Remote sensing of atmospheric water vapor in the region of Southwest China using GPS
No full textGPS technology provides a new powerful approach for measuring atmospheric water vapor. In this paper the experiment of observing integrated atmospheric water vapor or the precipitable water (PW) using ground-based GPS receivers performed in southwestern region of China is presented. Zenith total delay (ZPD) data are collected in a GPS network consisting of 10 stations. Time series of water vapor in one hour bins for 10 months is retrieved. The results of 3 stations in southwestern region affected by many monsoons show that the water vapor has large variability in spatial and temporal scales. The water vapor derived from GPS is compared with retrievals from the radiosondes. The GPS PW agrees well with data from radiosondes, which indicates GPS PW are correct at this locations. The difference of PW from them is larger when the humidity is higher and more variable in summer. The results of comparison with the NCEP reanalysis PW data show that they are consistent with each other. In the mountain areas where observations are few, PW from GPS can be used to validate the PW from numerical model analyses. Finally, long-term monitoring water vapor using ground-based GPS is discussing.Environmental SciencesMeteorology & Atmospheric SciencesOceanographyOpticsEICPCI-S(ISTP)
Dynamics of a SQUID ratchet coupled to a nanomechanical resonator
No full textWe investigate the dynamics of a superconducting rectifying circuit, namely, a three-junction superconducting quantum interference device (SQUID), where one arm of the superconducting loop consists of a nanomechanical resonator. We find that the dc characteristic curve of the system displays features that are directly related to the frequency and amplitude of the mechanical oscillations; these effects can be further enhanced by biasing the SQUID with an ac current. We discuss potential future developments of this idea in the field of ultrasensitive position detection, and assess their feasibility in current setup
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